Apparatus for printing lenticulated films



K. RANTSCH Feb. 23, 1937.

APPARATUS FOR PRINTING LENTICULATED FILMS Filed Aug. 50, 1934 PatentedFeb. 23, 1937 APPARATUS FOR PRINTING LENTICULATED FILMS Kurt Rintsch.Teltow-Seehoi, near Berlin, Germany. assignor to OpticolorAktiengesellschalt. Glarus, Switzerland, a Swiss corporation ApplicationAugust 30, 1934, Serial No. 742,188

2 Claims.

This invention relates to an improvement in apparatus for printinglenticular films. Usually the original lenticular films are taken in acamera provided with a polychromatic filter, the copy films areprojected in a projection apparatus which is provided with an equal orsimilar color filter.

In my co-pending application Ser. No. 688,545, filed September 8, 1933,I have described an optical printer for lenticular films including acopying lens and further optical means disposed in the path of lightpassing between the original and the copy film, said means causing theaperture of the copying lens to be seen from the lens elements of thefilms in a plurality of diflerent directions. This arrangement allows touse a copying lens which has a smaller relative aperture than thelenticular elements oi the films and therefore may have a goodcorrection. To obtain the desired effect it is advantageous as describedin my above mentioned application to produce a relative movement betweenthe films and the optical means disposed between the original and thecopy film.

It is frequently desirable in printing films to produce on the copy filmpictures 01' another scale as on the original film. For instance, astandard 35 mm. film shall be printed on a 16 mm. amateur film. It ispossible to use the optical printer described in my prior application inaltering the scale of the pictures, if the moved optical means on theside oi the original film and of the copy film oscillate with difi'erentamplitudes. In this case the oscillating optical means must be arrangedon diflerent separately driven supports. It is obvious that the opticalprinting process requires a great exactness with respect to the employedguiding means. There are more difiiculties to move and to guide twosupports than one support in all different positions with the necessaryexactness.

It is an object oi. the invention. to make use (in an optical printer oithe manner described above) of such a number or moved optical means.that the amplitude of oscillation of all the moved optical means isequal. According to the number oi the moved optical means the picturesof the films may be enlarged and reduced in difierent proportions.However, the alteration or scale is only possible in a ratio of wholenumbers. But this limitation is not an essential disadvantage, as it isalways possible, to bring about each practically desired enlargement orreduction by a ratio oi whole numbers. The most important case in thepractice is the printing from Germany September 1, 1933 standard 35 mm.film on 16 mm. amateur film. For this instance the ratio 2:1 or 1:2 maybe chosen with good approximation.

Other objects and advantages of this invention will be more fullyunderstood from the following description when read in connection withthe accompanying drawing in which the same reference characters denotethe same parts throughout and in which,

Fig. 1 is a diagrammatic view 01' an optical printer according to theinvention, the original film and an optical means on the side of thecopy film being moved, the ratio of the scales being 1:2;

Fig. 2 shows an optical printer, both the films being in rest, onemovable means being moved, the ratio of the scales being also 1:2;

Figs. 3 and 4 represent in diflerent positions several moved opticalmeans rigidly connected together, the ratio of the scales being also1:2;

Figs. 5 and 6 show also in different positions several moved opticalmeans rigidly connected together the ratio of the scales being 2:3.

In Fig. 1 the pictures on the original film I are printed by the copyinglens 2 on the copy film it. The pictures on the film it have double thesize as those on the film l. Between the copying lens 2 and the film I3the optical square I is arranged, so that the film is seen at II" fromthe copying lens. During the printing process the guiding means of thefilm I and the optical square 3 are set in motion in such a manner, thatthe positions designated by I, II and III are reached one after theother. As the copying lens 2 has double the distance from the film imageI!" as from the film I, the optical square 3 is arranged on half the waybetween the lens 2 and the film image i3". In this position the opticalsquare 3 has the same amplitude oi. oscillation as the film l.

The means for oscillating the various parts may comprise a crank pin 34on a revolving crank disk 35 rotating about its axis 38. The pin isconnected to a lever 33 which swings on a fixed pivot 32 and isconnected by links at one end to the film gate enclosing the film l andat the opposite end to the optical square 3.

While Fig. 1 represents an arrangement with two difierent oscillatingmeans which oscillate with the same amplitude, the optical printeraccording to Fig. 2 requires only one oscillating optical means. Forthis instance the pictures on the film I! have also double the size asthose on the film I. To avoid confusion, such oscillating means is notshown in Fig. 2, since it may be the I both original and copy films.Beyond this the same kind as shown in Figs. 3, 4, 5, and 6. The lightrays pass from the film I over the reflecting surface 4, the opticalsquare 6, the plane mirror 6, through the copying lens 2, over the planemirrors I and 8, the optical squares 9, Hi and H and finally over theplane mirror I! to the film It.

The whole path 01 rays from the film I to the lens I has half the lengthas the path from the lens 2 to the film It. The reflecting surfaces 4and 6 are rigidly connected to the optical squares 9 and II and movablyarranged towards the lens and the films, so that they may oscillate inthe directions or the double arrow l4. Hereby the image or the apertureof the copying lens seen from the films moves to such an extent for bothfilms, that the extreme rays from the copying lens to the films includethe same angle. The original film and the copy film have lenticulationsor lens elements of equal aperture, it being well known in the art thatthe standard aperture ior lenticulated film is F:2.5., This standard ispreferably used for films are seen from the copying lens in exactlyoppositedirections, as it is necessary for good printing. Another devicewhich is also adapted for enlargement and reductions in the ratio 1:2 isrepresented in two different positions of the moved optical means in theFigs. 3 and 4. Be-

tween the films and ll the objective 2 is mounted; on the one side theunmoved mirror IS with the moved optical square ll are arranged while onthe other side the unmoved mirror l8 and optical square I! and the movedoptical squares 20 and 2| are provided. The optical squares I1, 20 and2| are rigidly connected together, being exactly adjusted one to theother, and oscillate in such a manner. that they reach on the one sidethe extreme position shown in Fig. 4. The rays represented in thefigures pass from the point on the margin of the films to the points onthe margin of the copying lens. These extreme rays include all the otherrays of the beams of light which cause the reproduction of the pictures.

The Figs. 5 and 6 show an optical printer, the ratio of the scales ofthe original film and the copying film |3 being 2:3. Between the filmsthe unmoved copying lens 2, the unmoved mirrors and optical squares 22to 26 and the jointly and synchronically oscillating optical squares 21to 3| are arranged. Fig. 5 represents the mean position of the movedoptical means, while in Fig. 6, a side position is shown. The lengths ofthe paths of rays on the side of the original film and on the side ofthe copy film are in the ratio of 2:3.

In Figs. 2, 3, 4, 5, and 6, oscillation may be caused by a devicesimilar to that shown in Fig. 1 and including the same crank disk 35which is employed to reciprocate a frame I! supported in guides 31,

In all or the figures of the drawing, the light path between theoriginal film and the copy film is shown by a dot and dash line, itbeing understood that any suitable source oi light may be employed forthus transmitting light through the original film to the copy film andby aid oi the optical elements shown, either by themselves or with theaid of additional elements known in the art.

It is advantageous to provide a split shaped diaphragm in the objective,the direction of the split being perpendicular to the direction of theoscillating movement. A further improvement 01' the quality of the.pictures may be obtained by using a punctiiorm diaphragm opening. I

The' devices represented in" the Figs. 2-8 have over the device shown inFig. 1 the advantage. that the film guiding means are firmly arranged,

whereby a greater exactness and a better quality disposed in said pathbetween said lens and arranged in two sets, one set between the lens andcopyfilm and the other between the lens and original film, and means formoving said sets transversely or said path, the amplitude of movement ofone set being substantially equal to the amplitude of movement or theother set.

2. In combination, an original lenticulated film and a copy lenticulatedfilm, means forming an optical path for the passage or light from theoriginal to the copy film, said means including a relatively fixedcopying lens 01' smaller aperture than the lenticulations or said filmsand disposed in said path nearer one film than the other, and alsoincluding a plurality of reflecting surfaces disposed in said pathbetween said lens and arranged in two sets, one set between the lens andcopyfilm and the other between the lens and original film, and means formoving said sets transversely of said path, the amplitude of movement ofone set being substantially equal to the amplitude of movement or theother set and the number of refiecting surfaces in one set being greaterthan that in the-other set.

KURT RANTSCH.

